sicalifornia and one from pennsylvania and another from west virginia have contracted the virus. three of those eight have died. there are linked to cabins at yosemite curry village. we now know that one case originated in another section of the park. dan kerman has more on what you need to know about this disease. >> typically people are infected by exposure to deer mice droppings and urine. you do not have to touch those droppings to be exposed. >> the most common way to get invested is if you inhale contaminated dust. >> cleaning the deaths must be done in a specific way. >> did not sweep the desk. that will simply get the dust into the air and expose you to a fax. it isn't for and use a wet towel, ideally would be a wet towel with a 10 percent lead. you cover the area to prevent the desk from getting into the air. >> deer mice are most common and upper elevations of the sierra. if you are going camping, a few extra tips, first of all, make sure you lock up food and drinks as to not attract deer mice. definitely do not sleep on the grounds. remember, that can contain the test